I have a 2003 996TT, EVOMOS II, PSS10s, front and rear sway bars (set to the middle). I have Michelin PS2s 235.35.19 & 315.25.19. It's been this way for several years and has been running and handling fine, after addressing some initial twitchiness when I went to the 19s.

For the past 6 months to has been increasingly loose in the rear end under hard acceleration. It rocks significantly from side to side when I get on it hard, and I have to let off the gas to let it settle down so I can get on it again. At first it was subtle but now it progressively getting worse and I don't feel safe making fast passes under full throttle (which sucks!). It still handles well through curves (no increase in body roll, under/over steer).

Tires are 80% worn and are getting replaced in the spring, but the issue doesn't feel traction related, more so suspension or maybe even differential. Anyone else experienced this?

 

FWIW- I had some MPCups on my car that may have had one too many heat cycles and I thought the car had huge suspension problems. I swapped them out for cheap street rubber (Hankook V12) and the car completely transformed itself.

 

Interesting. Unfortunately I won't be able to test that theory until spring.

I just got back from a shakedown drive and noticed a few new and unwelcome "clunks" in the rear end when I go over big bumps / potholes, so I might have something loose back there or a bad bushing, stabilizer link, etc. I'm taking it in this week for fluid changes so when it's up in the air I'm going to give the suspension a full inspection. I'll report my findings afterwards.

Thanks for your input.

 

What kind of drop links? Those are common points of failure.

 

I experienced this once when the rear lower control arm bolt on the right rear was loose at the subframe connection point.

Jack the car up and see if there is any play, either up and down or fore and aft.

easy fix if that's the problem.

BTW, for me this was right after an alignment. Always check all of your suspension bolts for tightness after an alignment.

 

just had the same issue tire pressure and a new alignment and its alot better still a little wobble but not much it was real bad a week ago. i went with a european turbo alignment. im riding really low so i have to stiffen things up a bit to hopefully clear all the wobble up

 

Mine felt the same way once. Turned out the alignment was all wacked out

 

Mine was doing something similar with low tire pressure (slow leak) on RR tire.

 

I had the exact same issue and replaced all 4 tires, had an alignment done and made sure the tire pressures were exact. After all of these issues, I still had the rocking motion from side to side, but just a lot less.

Took it to my independent mechanic and he suggested that maybe an axle was bad, so proceeded to do the RWD conversion and full GT2 slave conversion. After this was done there is no rocking back and forth and the only issue now is spinning the wheels through 1st, 2nd, and part of 3rd gear. One of my front axles had some play in it causing the rocking back and forth.

 

Thanks everyone...I've got some leads to chase now. Much appreciated.

 

Not 100% sure, that was done by previous owner. It will get a thorough inspection and I plan to re-check the torque on all of the suspension hardware when I'm under there.

 

You nailed it. One was real bad and the other was on it's way. They were the OE links. after replacing them and adding a bit of pressure to the tires (I went 35 front / 39 rear) the wiggle went away completely. I love it when a fix is simple and cheap...it doesn't happen often.


Thanks again to all for the input.

 

glad i came across this, mines doing the same thing, after i replace my rear tires i'll start searching for the others!

 

for big power the rear axle has to much flex in oem configuration. Rear axle tie rod uniball and track rod rear stiffer siltentblocks you need.

 

just noticed this morning, that it wiggles back and forth even under slow acceleration too.